Thank you for the add . I've already started on my 30 gallon drum and the lid is a 2" bunge I was wondering what size holes to drill for the intake vents for the proper draft flow I was thinking two 2" on opposite sides thanks in advance for the newb question.

I used 3 of these Weber grill replacement dampers on mine (which is an 85 gallon drum) and it is (for the most part) overkill. Each hole I believe is 3/4" in diameter. It is handy to have all of them open when I'm trying to get the coals going but it's not necessary. I'd go with at least one 2" if you plan on using any type of electronic temperature control device (which in my opinion is not necessary on a drum). If I built another one I would go with 2 of the Weber dampers though. IMO it's always better to have too much intake than not enough.